600mm Box bend brake (Finger Brake, pan Brake)

[RotarySMP]

A guy Simco on an Australian woodworking site has posted a great set of plans, with photos how to build a 600mm finger brake for bending sheet metal.

http://www.woodworkforums.ubeaut.com...ad.php?t=45792

He has graciously donated this design to the online community.

As I have a sheet metal homebuilt aircraft project, I have been looking for a good design for a small brake, but until Simco's design, all the ones I had seen were either very primitive clamp an angle iron to bench type things, or Larry McFarlands very large, very tasty 8 ft brake, which I simply don't have space for.
http://www.macsmachine.com/

The thing I really like about Simco's design is that it has both set back and apron height adjustment, allowing you to control the bend radius, and it is a box brake, so you can remove and adjust the clamping fingers to make boxes and other complex shapes.

I have attached photos from the original forum, showing Simco's original brake, and one by a guys called Rod.

[RotarySMP]

I started my build by scrounging the scrap bin for some stock to make the adjustment cams. I decided to personalize it a little and use round rather than Hex cam adjusters.

[RotarySMP]

The steel I ordered came to €125 from metal supermarkets. Pretty steep I thought, but I guess the price of metals has gone crazy lately.

This is going to be good exercise, as I have no power hacksaw, and my mill is in a friends shed an hour out of town. I'll start by sawing as much as I can and make the parts I can on the lathe here, then go and finish the milled bits.

These are going to be the end plates.

[RotarySMP]

And these will be part of the closing mechanism.

[RotarySMP]

Continued work on these closing arms today. All this hacksawing should be good exercise.

After I had them roughed, I cleaned then and superglued them together.

Drilled the pilot holes so that they would match using the tailstock as a drill press.

I started setting them up on the lathe for fly cutting. It is a bit late to do intermittent cuts - the neighbors wouldn't be thrilled.

[RotarySMP]

Busy week with trips to Milan and Aachen, so I only just got back to Brenda.

Finished fly cutting the two closing arms surfaces which are short enough to do on the lathe, and then some more hacksawing, cutting finger blanks in different widths, and the leaf to length.

[RotarySMP]

Finished cutting out the finger blanks. I have 2x 25mm, 2x 50mm, 2x 75mm, 1x 100m, and 1x 200mm wide fingers. I need to make 2x 15mm wide and one 20mm wide, then I can cover every 5mm increment from 15mm up.

I also made a #2 morse centering widget with hardened pin to ease the centering of parts on the mills rotary table.

[RotarySMP]

Made an arbor for some old saw blades I have. Will need them when I cut down the angle iron for the closing frame.

Since my mill has an ER 16 spindle, the largest collet is only 10mm. I had to turn down the shaft on my smallest flycutter, and made a nice cutting bit for it.

[RotarySMP]

Been ages since I posted an update.

Machining the round shapes has been a slow process, as my mill is an hour away.

The mini lathe swing is too limited to turn the bores, so I milled them with the rotary table. The surface finish is pretty bad, but they only see static loads. I might turn up some brass bushes.

I the parts were machined while superglued together. They fell apart today, although I still have the 20mm holes to drill. Not a problem, I can pin them and reglue them.

[RotarySMP]

To cut out the side pieces, I hack sawed as far as possible (I could have cutt the stock in half, to make things easier, but that would be a waste of a nice big offcut).

Then the outline was stop drilled. I used my Proxxon mini grinder with cutoff disks (about 10 discs) to weaken the remaining steel, and then finished cutting out with a cold chisel and hammer. These plate have now been superglued as well.

[RotarySMP]

Got a good session in on Sunday. While I have the loan of a friends little Chinese drill press, I am making the most of it.

Drilled the holes in the end plates and closing arms out to 14mm (the little drill press runs out of grunt about then).

Turned down a 130x60x16mm bar stock into the two pivots you see here for the closing arms.

[acondit]

Mark,

It looks like you are making good progress.

Alan